1. Field of the Invention
The present invention relates to a safety lid for use with conventional mugs or beverage containers. In particular, the present invention relates to a safety lid provided with a sealing means which securely retains the lid at the mouth of the mug or beverage container to prevent spillage of the liquid contained therein.
2. Description of the Related Art
The present invention is applicable to mugs and beverage containers alike, which shall hereinafter be collectively referred to as "mugs". The present invention shall also be described hereinbelow in connection with a conventional mug, although it will be appreciated that the principles of the present invention are also applicable to all conventional beverage containers.
There are many safety lids that are provided for use with mugs. These safety lids perform two primary functions: (1) to cover the open mouth of the mug to prevent the liquid contained in the mug from spilling, and (2) to maintain the temperature of hot liquid in the mug by preventing the escape of steam. It is expected that such safety lids be provided at low cost to the public.
Many of the currently-available safety lids suffer from a number of drawbacks, the most serious being that these lids are not securely retained at the mouth of the mug, which allows spillage of the liquid if the mug is tipped over. These lids also make it inconvenient for a user to drink from the mug, since an insecure lid usually means that the user must hold the lid while drinking.
Several attempts have been made to remedy this drawback. For example, snap-fit lids were provided, but they are unreliable since they must be entirely snapped in place to be effective.
Another example is U.S. Pat. No. 4,582,218 to Ross, which discloses a mug 10 which is specifically provided with a recessed shelf 30 extending inwardly from the internal wall 20 of the mug 10. Gaps 32 are provided in the shelf 30. A lid 40 is provided with tongues 48 and 50, which are adapted to be inserted through the gaps 32. The lid 40 is then rotated about the shelf 30 to secure the lid 40 to the mouth of the mug 10.
As a further example, U.S. Pat. No. 5,018,636 to Ross also discloses a mug 10 with a recessed shelf 30. However, the lid 40 is provided with a pair of retaining means 60 and 70, in the form of a flexible elongated rod 62 or 72 extending from the lower surface 46 of the lid 40 and having a spherical ball 64 or 66 provided at the end of the rod 62. In use, the lid 40 may be inserted into the mug 10 such that the lower surface 46 of the lid 40 rests on the upper portion 31 of the recess 30, with the flexible rods 62 and 72 bent inwardly, and the balls 64 and 66 resting adjacent the lower portion 38 of the recess 30.
Yet another example is U.S. Pat. No. 5,102,000 to Feltman, III, which discloses a mug 11 having an inwardly projecting ring 16 with vertical passages 17 and latch notches 18 formed in the ring 16. The lid 15 has a pair of flexible fingers 30, each having a rounded end 29. In use, the lid 15 is inserted into the mouth of the mug 11 such that the rounded ends 29 pass through the vertical passages 17. The lid 15 is then rotated so that the rounded ends 29 are fitted in the latch notches 18 to provide a secure fit.
While each of the above-described mug and lid combinations provide a somewhat secure fit of the lid to the mouth of the mug, they suffer from other drawbacks. The primary drawback is that, in each of the Ross '218, Ross '636 and Feltman devices, a specific mug and lid combination must be provided. Therefore, each of these mugs must be used with its intended lid. In fact, none these lids can be adapted for use with conventional mugs since conventional mugs do not have the required internal ring or shelf having passages or notches formed therein.
Additionally, these structural features often make the mug look aesthetically unappealing and cumbersome because they add a number of components that are not ordinarily provided on conventional mugs. Some of these lids require that the mug include an unsightly neck portion. The use of these lids is also complicated in that much manipulation, twisting and turning is needed to secure the lid in place. These lids are also ineffective if not properly secured.
Thus, there is a need for a safety lid that may be adapted for use with any conventional mug, is easy to use, can be provided at low cost, and which effectively secures the lid to the mouth of the mug to prevent spillage.